Technical Field
The present invention relates to a method for eliciting a plant immune response by seed priming of a Bacillus spp. culture solution treated at high temperature. More specifically, it relates to Bacillus spp. strains PB69 and 1628 for eliciting induced systemic resistance and promoted plant growth in a plant, a method of eliciting induced systemic resistance and promoted growth in a plant by using high pressure-sterilized culture solution of the aforementioned strains, a method of controlling a plant disease by using high pressure-sterilized culture solution of the aforementioned strains, a composition for eliciting induced systemic resistance and promoted growth in a plant containing, as an active ingredient, high pressure-sterilized culture solution of the aforementioned strains, a composition for controlling plants diseases containing, as an active ingredient, high pressure-sterilized culture solution of the aforementioned strains, a method for treating a seed to elicit induced systemic resistance and promoted growth in a plant by using the aforementioned composition, a method for treating a seed to control plant diseases by using the aforementioned composition, and a primed seed produced by the aforementioned method.
Background Art
Traditionally, methods for inhibiting and controlling an occurrence of plant pathogens have been studied for young plants, and chemically synthesized agrochemicals are mainly used for the methods. However, due to a negative effect of those chemically synthesized agrochemicals on an environment and a human body, their use is now being limited. Further, as an attention is currently paid to the control from a seed stage, studies on development of healthy and strong seeds are actively carried out.
Once rooted, a plant can never move. Thus, in order to have effective response to a change in external environment, a signal transduction system with inside of a plant has been developed. In particular, there is an immune system for fighting against attacks by various pathogens. Such resistant reaction includes induced systemic resistance (ISR) in which resistance is shown not only in a leaf attacked by a pathogen but also in an entire plant which has not been attacked and systemic acquired resistance (SAR) in which resistance is shown for other various pathogens which follow later. Among various agents for inducing SAR, BTH (benzo(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester, benzothiadiazole) is known as a substance which exhibits the most potent efficacy. However, a serious problem was found for those SAR-inducing agents which have been believed to be useful for overcoming the problems of agrochemicals, i.e., plant growth is inhibited when crops grown in an actual field are treated with them or a harvest amount is significantly lowered compared to a control group with no treatment. From the viewpoint of physiology, this phenomenon was regarded as “allocation fitness cost” phenomenon in which, by expressing many pathogen-related genes even in the absence of pathogens, under limited resources condition plant energy is over-consumed so that plant growth is inhibited as the energy to be used for growth is consumed for having resistance against diseases.
As such, inventors of the present invention selected a Bacillus sp. strain which exhibits an activity of eliciting induced systemic resistance similar to BTH and has an effect of promoting plant growth and controlling plant diseases, and tried to determine the seed priming effect of the high pressure-sterilized culture solution of the Bacillus sp. strain.
Meanwhile, “Bacillus sp. PB25 strain derived from soil and use thereof” is described in Korean Patent Application Publication No. 2012-0075936, and “Microbial polyglucosamine PGB-2 produced and secreted by Citrobacter sp. BL4 and use thereof” is disclosed in Korean Patent Registration No. 0678615. However, a method for eliciting a plant immune response by seed priming of heat (high temperature)-treated Bacillus culture solution of the present invention has never been disclosed.